1. Field of the Invention
The present invention relates to a display device that includes a display unit having a plurality of scanning lines and a plurality of signal lines and displays an image and a display method.
2. Description of the Related Art
For example, so-called flat panel displays (hereinafter, referred to as FPDs), such as a liquid crystal display, an organic EL (Electro Luminescence) display, a plasma display, and an FED (Field Emission display) have been widely spread.
The FPD uses a fixed pixel method that fixedly arranges pixels in the horizontal direction and the vertical direction and performs image display.
The quality of a moving picture displayed by the FPD is not sufficiently higher than that of, for example, a CRT (Cathode Ray Tube) display according to the related art. Therefore, it is necessary to improve the image quality of the FPD. For example, the problems arising in the display of a moving picture include so-called motion blur and jerkiness which is perceived as an overlap image.
These problems are caused by, for example, the delay of a screen switching response speed or hold-type display in the case of a liquid crystal display. In the hold-type display, while images are continuously displayed for one frame period, the observer determines that the displayed object is being moved and moves the eyes in the traveling direction of the object. Therefore, there is a deviation between the actual display position and the view position, and the deviation is accumulated in the retina, which is perceived as motion blur.
For example, low time reproducibility in image display causes the deterioration of the quality of a moving picture, such as motion blur. Therefore, in order to improve the quality of the moving picture, it is effective to increase the frame rate and improve the time reproducibility.
In order to increase the frame rate, for example, there is a method of simultaneously driving a plurality of adjacent scanning lines. Specifically, in general, one scanning line is driven for one horizontal line period. However, in this case, a plurality of scanning lines are simultaneously driven.
FIG. 40 is a diagram illustrating an example of the detailed structure for simultaneously driving a plurality of lines to improve the frame rate.
The structure shown in FIG. 40 corresponds to when two adjacent scanning lines are simultaneously driven for one horizontal line period.
In FIG. 40, a pixel array 100 corresponds to a so-called dot matrix image display and includes a plurality of scanning lines 100a, as shown in FIG. 40. Although not shown in FIG. 40, the image array 100 includes a plurality of signal lines intersecting the plurality of scanning lines 100a. A set of a transistor (switch) and a storage capacitor is provided at each of the intersections of the scanning lines 100a and the signal lines. One set of the transistor and the capacitor forms one pixel.
When a driving voltage is applied to the scanning line 100a, each transistor connected to the scanning line 100a is turned on and signal values can be written to each pixel including the transistor (active state). Then, when a voltage corresponding to an input image (corresponding to one line) is applied to each signal line, the signal value can be written to each pixel on the scanning line 100a in the active state. In general, the driving voltage is sequentially applied to the scanning lines 100a to select the scanning lines, and an image corresponding to one frame is sequentially displayed on the lines.
In the structure shown in FIG. 40, as the drivers (line driving circuit) that apply the driving voltage to the scanning lines 100a, a driver 101 and a driver 102 are provided as shown in FIG. 40. A switch circuit 103 including a plurality of switches each capable of simultaneously supplying the output voltage of the driver 101 to each set of two scanning lines 100a is provided between the driver 101 and the scanning lines 100a. In addition, a switch circuit 104 including a plurality of switches each capable of simultaneously supplying the output voltage of the driver 102 to each set of two scanning lines 100a, which is different from the set of two scanning lines 100a supplied with the driving voltage by the switch circuit 103, is provided between the driver 102 and the scanning lines 100a. 
The on/off operations of the switch circuit 103 are controlled by an ON/OFF control signal. Specifically, the switch circuit 103 turns on the plurality of switches when the ON/OFF control signal is at an H level.
The ON/OFF control signal is supplied to the switch circuit 104 through an inverting circuit 105. The switch circuit 104 turns on the plurality of switches included therein when the input signal from the inverting circuit 105 is at an H level (the period for which the switch circuit 103 is turned off).
During the period for which the ON/OFF control signal is at an H level, the driver 101 outputs a sequential driving voltage to each set of two switches of the switch circuit 103. As a result, it is possible to apply the sequential driving voltage to each set of two scanning lines 100a of the pixel array 100.
During the period for which the ON/OFF control signal is at an L level, the driver 102 outputs the sequential driving voltage to each set of two switches of the switch circuit 104. As a result, during the period, it is possible to apply the sequential driving voltage to each set of two scanning lines 100a during a period that is different from that for which the switch circuit 103 is turned on in the pixel array 100.
According to the structure shown in FIG. 40, since a plurality of scanning lines are simultaneously driven, it is possible to reduce the time required to scan one frame. As a result, it is possible to improve the frame rate. Specifically, in the example shown in FIG. 40, the time required to scan one frame is half the general scanning time. It is possible to increase the frame rate to be two times higher than that when general one line sequential scanning is performed.
When the frame rate is improved, the quality of a moving picture is improved.